rand/randmts.c: Use init2, as size of variables is known in advance.

1 files changed, 11 insertions, 14 deletions

diff --git a/rand/randmts.c b/rand/randmts.c
index e3b033885..55fdfa192 100644
--- a/rand/randmts.c
+++ b/rand/randmts.c
@@ -1,6 +1,6 @@
 /* Mersenne Twister pseudo-random number generator functions.
 
-Copyright 2002, 2003 Free Software Foundation, Inc.
+Copyright 2002, 2003, 2013 Free Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
 
@@ -25,16 +25,15 @@ along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
 /* Calculate (b^e) mod (2^n-k) for e=1074888996, n=19937 and k=20023,
    needed by the seeding function below.  */
 static void
-mangle_seed (mpz_ptr r, mpz_srcptr b_orig)
+mangle_seed (mpz_ptr r)
 {
   mpz_t          t, b;
   unsigned long  e = 0x40118124;
   unsigned long  bit = 0x20000000;
 
-  mpz_init (t);
-  mpz_init_set (b, b_orig);  /* in case r==b_orig */
+  mpz_init2 (t, 19937L);
+  mpz_init_set (b, r);
 
-  mpz_set (r, b);
   do
     {
       mpz_mul (r, r, r);
@@ -43,7 +42,7 @@ mangle_seed (mpz_ptr r, mpz_srcptr b_orig)
       for (;;)
         {
           mpz_tdiv_q_2exp (t, r, 19937L);
-          if (mpz_sgn (t) == 0)
+          if (SIZ (t) == 0)
             break;
           mpz_tdiv_r_2exp (r, r, 19937L);
           mpz_addmul_ui (r, t, 20023L);
@@ -51,7 +50,7 @@ mangle_seed (mpz_ptr r, mpz_srcptr b_orig)
 
       if ((e & bit) != 0)
         {
-          e &= ~bit;
+          e ^= bit;
           mpz_mul (r, r, b);
           goto reduce;
         }
@@ -107,15 +106,15 @@ randseed_mt (gmp_randstate_t rstate, mpz_srcptr seed)
 
   p = (gmp_rand_mt_struct *) RNG_STATE (rstate);
 
-  mpz_init (mod);
-  mpz_init (seed1);
+  mpz_init2 (mod, 19937L);
+  mpz_init2 (seed1, 19937L);
 
-  mpz_set_ui (mod, 0L);
   mpz_setbit (mod, 19937L);
   mpz_sub_ui (mod, mod, 20027L);
   mpz_mod (seed1, seed, mod);	/* Reduce `seed' modulo `mod'.  */
+  mpz_clear (mod);
   mpz_add_ui (seed1, seed1, 2L);	/* seed1 is now ready.  */
-  mangle_seed (seed1, seed1);	/* Perform the mangling by powering.  */
+  mangle_seed (seed1);	/* Perform the mangling by powering.  */
 
   /* Copy the last bit into bit 31 of mt[0] and clear it.  */
   p->mt[0] = (mpz_tstbit (seed1, 19936L) != 0) ? 0x80000000 : 0;
@@ -124,14 +123,12 @@ randseed_mt (gmp_randstate_t rstate, mpz_srcptr seed)
   /* Split seed1 into N-1 32-bit chunks.  */
   mpz_export (&p->mt[1], &cnt, -1, sizeof (p->mt[1]), 0,
               8 * sizeof (p->mt[1]) - 32, seed1);
+  mpz_clear (seed1);
   cnt++;
   ASSERT (cnt <= N);
   while (cnt < N)
     p->mt[cnt++] = 0;
 
-  mpz_clear (mod);
-  mpz_clear (seed1);
-
   /* Warm the generator up if necessary.  */
   if (WARM_UP != 0)
     for (i = 0; i < WARM_UP / N; i++)